Project Summary/Abstract Aggressive/challenging behaviors (AC/Bs) are a major public health problem for individuals with intellectual disabilities (ID) living in group homes. A leading reason for psychiatric hospitalizations and incarcerations, A/CBs are costly to the healthcare system, agencies and families. Social problem solving (SPS) training programs for individuals with ID have had positive behavioral results, but most were conducted in clinical or forensic settings. None were community-based preventive interventions, none examined whether A/CBs decreased in participants? group homes and work settings, and none addressed cost effectiveness. In our preliminary work, we modified an effective SPS training program, using input from individuals with ID and residential staff, as a preventive intervention for the group home setting. Steps to Effective Problem-solving (STEPS) includes residential staff and uses the group home environment to facilitate behavior change. The purpose of this clinical trial is to test the efficacy of STEPS for individuals with ID. Specific aims are to 1) Assess the efficacy of the STEPS intervention in group homes to improve SPS skills and reduce A/CBs of the individuals with ID compared to an attention-control nutrition program from baseline to 12, 24 and 36 weeks, controlling for behavioral determinants of A/CBs (demographics, agency/home environment, current health). 2) Assess the mediating effect of the support environment for SPS (residential staff SPS skills, group home level SPS skills, and group cohesiveness) on the improvement of SPS skills and reductions in A/CBs. 3) Evaluate cost effectiveness of STEPS relative to usual care for A/CB incidents in group homes. .A cluster-randomized clinical trial design will be used in which 36 group homes (18 male, 18 female) will be randomly assigned to STEPS or attention-control. We will recruit 180 individuals with mild to moderate ID, at least 18 years old (approximately 5 per home), and at least two residential staff from each home (2-3 per home). SPS outcomes will be assessed with Iowa Family Interactions Rating Scales (IFIRS) Individual-level Problem-solving Scales and the Problem-solving Task. A/CB outcomes will be assessed with IFIRS Dyadic-interaction Scales, General Maladaptive Index (agency, work settings), and incident reports (agency). Mediating effects will be assessed for residential staff with SPS Inventory Revised- Short Form and IFIRS Individual-level Problem-Solving Scales; for group home level SPS skills by IFIRS Group Level Problem-Solving scales; and for group cohesiveness by the Cohesiveness subscale of Group Environment for the Intervention Scale. Cost- effectiveness of STEPS will be evaluated taking into account costs of A/CBs borne by the participant and family, program, group home, healthcare system, and public services. STEPS will be compared to usual care, (control group costs of behavior incidents). We expect to show STEPS to be a preventive behavioral strategy to reduce A/CBs among individuals with ID, improve the cost effectiveness of their care and make an important incremental advance in SPS research.